Prelude.js

/* global exports */
"use strict";

// module Prelude

//- Functor --------------------------------------------------------------------

exports.arrayMap = function (f) {
  return function (arr) {
    var l = arr.length;
    var result = new Array(l);
    for (var i = 0; i < l; i++) {
      result[i] = f(arr[i]);
    }
    return result;
  };
};

//- Bind -----------------------------------------------------------------------

exports.arrayBind = function (arr) {
  return function (f) {
    var result = [];
    for (var i = 0, l = arr.length; i < l; i++) {
      Array.prototype.push.apply(result, f(arr[i]));
    }
    return result;
  };
};

//- Monoid ---------------------------------------------------------------------

exports.concatString = function (s1) {
  return function (s2) {
    return s1 + s2;
  };
};

exports.concatArray = function (xs) {
  return function (ys) {
    return xs.concat(ys);
  };
};

//- Semiring -------------------------------------------------------------------

exports.intAdd = function (x) {
  return function (y) {
    /* jshint bitwise: false */
    return x + y | 0;
  };
};

exports.intMul = function (x) {
  return function (y) {
    /* jshint bitwise: false */
    return x * y | 0;
  };
};

exports.numAdd = function (n1) {
  return function (n2) {
    return n1 + n2;
  };
};

exports.numMul = function (n1) {
  return function (n2) {
    return n1 * n2;
  };
};

//- ModuloSemiring -------------------------------------------------------------

exports.intDiv = function (x) {
  return function (y) {
    /* jshint bitwise: false */
    return x / y | 0;
  };
};

exports.intMod = function (x) {
  return function (y) {
    return x % y;
  };
};

exports.numDiv = function (n1) {
  return function (n2) {
    return n1 / n2;
  };
};

//- Ring -----------------------------------------------------------------------

exports.intSub = function (x) {
  return function (y) {
    /* jshint bitwise: false */
    return x - y | 0;
  };
};

exports.numSub = function (n1) {
  return function (n2) {
    return n1 - n2;
  };
};

//- Eq -------------------------------------------------------------------------

exports.refEq = function (r1) {
  return function (r2) {
    return r1 === r2;
  };
};

exports.refIneq = function (r1) {
  return function (r2) {
    return r1 !== r2;
  };
};

exports.eqArrayImpl = function (f) {
  return function (xs) {
    return function (ys) {
      if (xs.length !== ys.length) return false;
      for (var i = 0; i < xs.length; i++) {
        if (!f(xs[i])(ys[i])) return false;
      }
      return true;
    };
  };
};

exports.ordArrayImpl = function (f) {
  return function (xs) {
    return function (ys) {
      var i = 0;
      var xlen = xs.length;
      var ylen = ys.length;
      while (i < xlen && i < ylen) {
        var x = xs[i];
        var y = ys[i];
        var o = f(x)(y);
        if (o !== 0) {
          return o;
        }
        i++;
      }
      if (xlen === ylen) {
        return 0;
      } else if (xlen > ylen) {
        return -1;
      } else {
        return 1;
      }
    };
  };
};

//- Ord ------------------------------------------------------------------------

exports.unsafeCompareImpl = function (lt) {
  return function (eq) {
    return function (gt) {
      return function (x) {
        return function (y) {
          return x < y ? lt : x > y ? gt : eq;
        };
      };
    };
  };
};

//- Bounded --------------------------------------------------------------------

exports.topInt = 2147483647;
exports.bottomInt = -2147483648;

exports.topChar = String.fromCharCode(65535);
exports.bottomChar = String.fromCharCode(0);

//- BooleanAlgebra -------------------------------------------------------------

exports.boolOr = function (b1) {
  return function (b2) {
    return b1 || b2;
  };
};

exports.boolAnd = function (b1) {
  return function (b2) {
    return b1 && b2;
  };
};

exports.boolNot = function (b) {
  return !b;
};

//- Show -----------------------------------------------------------------------

exports.showIntImpl = function (n) {
  return n.toString();
};

exports.showNumberImpl = function (n) {
  /* jshint bitwise: false */
  return n === (n | 0) ? n + ".0" : n.toString();
};

exports.showCharImpl = function (c) {
  return c === "'" ? "'\\''" : "'" + c + "'";
};

exports.showStringImpl = function (s) {
  return JSON.stringify(s);
};

exports.showArrayImpl = function (f) {
  return function (xs) {
    var ss = [];
    for (var i = 0, l = xs.length; i < l; i++) {
      ss[i] = f(xs[i]);
    }
    return "[" + ss.join(",") + "]";
  };
};